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Significance of thrombin in bleomycin-induced pulmonary fibrosis.

To clarify the role of thrombin in fibroblast growth and the development of pulmonary fibrosis in bleomycin-induced interstitial lung disease, we examined the relationship of thrombin activity to fibroblast growth-stimulating activity (FGA) in bronchoalveolar lavage fluid (BALF) from bleomycin-treated rats. Male Wistar rats were given a single intratracheal injection of bleomycin, bronchoalveolar lavage was performed 2, 6 and 15 days later, and the BALF was assayed for thrombin activity and FGA. Higher FGA than the control value was detected in the BALF from rats on Day 6 after bleomycin administration. In bleomycin-treated rats, thrombin activity in the BALF was significantly elevated on Day 2, and maximal on Day 6. The FGA of the BALF from bleomycin-treated rats on Day 6 was significantly decreased by its treatment with various thrombin inhibitors, such as alpha 1-antitrypsin, antithrombin III, hirudin and MD-805. On ammonium sulfate fractionation most of the thrombin activity was recovered in the fraction of 35-50% saturation in which most of the FGA was detected. These results suggest that the FGA of the BALF from bleomycin-treated rats was at least partly due to thrombin, and that thrombin is responsible, at least in part, for fibroblast growth and pulmonary fibrosis in bleomycin-induced interstitial lung disease.

Animals↗

Increased serum levels of endostatin in patients with idiopathic pulmonary fibrosis.

Endostatin is an angiogenesis inhibitor that is an endogenously produced proteolytic fragment of type XVIII collagen. Serum levels of endostatin have been studied extensively in patients with malignant diseases. Recently, elevated serum endostatin levels were observed in patients with systemic sclerosis accompanying pulmonary fibrosis. To determine whether elevated serum endostatin can be observed in patients with idiopathic pulmonary fibrosis (IPF), we measured serum levels of endostatin in 69 patients with benign respiratory disease using an ELISA kit. The median of the serum endostatin levels in these patients was 50.8 pg/mL. Seven of 11 patients (63.6%) with collagen disease-associated pulmonary fibrosis (CDPF), and 19 of 24 patients (79.2%) with IPF had higher serum endostatin levels than the median level of the 69 patients. There was no statistical difference in serum endostatin levels between the patients with IPF and those with CDPF (P=0.7898). Serum endostatin levels in 24 patients with IPF were significantly higher than those in 34 patients with respiratory diseases other than IPF and CDPF (P=0.0001). Elevated serum levels of endostatin were observed in patients with IPF. Although the mechanisms are unclear, elevated serum levels of endostatin may be related to the fibrosing process in the lung.

Adult↗

Immunolocalization of SPARC, tenascin, and thrombospondin in pulmonary fibrosis.

Several biochemically unrelated multifunctional extracellular proteins, SPARC, thrombospondin 1, and tenascin-C (TN), have been grouped as antiadhesive glycoproteins because they inhibit the spreading of cells on extracellular matrix in vitro. Migration of fibroblasts and epithelial cells into the air spaces to organize inflammatory exudate is a feature common to several fibrosing lung diseases. We hypothesized that migration would be facilitated by loosening the adhesive interactions between cells and the pericellular matrix components of the alveolar wall and that one or more of the anti-adhesive glycoproteins could be involved. Immunohistochemistry was used to localize SPARC, TN, and thrombospondin 1 in biopsies of organizing pneumonia, idiopathic pulmonary fibrosis (nine cases of usual interstitial pneumonia, one of desquamative interstitial pneumonia), and control lungs. Each antigen had a distinctive distribution. Only TN was expressed in control lungs, where it strongly stained the basement membrane of large bronchi and weakly stained alveolar entrance rings and small veins. In organizing pneumonia, TN was heavily stained through the entire extracellular matrix of the Masson bodies. In idiopathic pulmonary fibrosis, TN was abundant in the fibroblast foci of active fibrosis but was also present in the basement membrane regions beneath the metaplastic epithelium lining honeycomb cysts. TN was abundant in the interstitium in desquamative interstitial pneumonia. SPARC was observed only intracellularly where it occurred in the fibroblasts of Masson bodies of organizing pneumonia and the fibroblast foci of usual interstitial pneumonia. In desquamative interstitial pneumonia, expression of SPARC was minimal, in rare interstitial fibroblasts. Thrombospondin 1 was found consistently in organizing pneumonia but only infrequently in idiopathic pulmonary fibrosis. In both, it was localized in the extracellular matrix immediately beneath reparative epithelium. These results are consistent with a role for SPARC in fibroblast migration. TN may function in both fibroblast migration and the adhesion of metaplastic bronchial-type epithelium. However, these proteins also have other activities that may be important in pulmonary fibrosis. The localization of thrombospondin 1 suggests that it may be synthesized by regenerating epithelium where it may aid in the adhesion or migration of the epithelial cells.

Antibodies, Monoclonal↗

Thrombin enhances lung fibroblast proliferation in bleomycin-induced pulmonary fibrosis.

To clarify the role of thrombin in fibroblast growth and the development of pulmonary fibrosis in bleomycin-induced interstitial lung disease, we examined the relationship of thrombin activity to fibroblast growth-stimulating activity (FGA) in bronchoalveolar lavage (BAL) fluid from bleomycin-treated rats. Male Wistar rats were given a single intratracheal injection of bleomycin, BAL was performed 2, 6, and 15 days later, and the BAL fluid was assayed for thrombin activity and FGA. Higher FGA than the control value was detected in the BAL fluid from rats on day 6 after bleomycin administration. In bleomycin-treated rats, thrombin activity in the BAL fluid was significantly elevated on day 2 and maximal on day 6. The FGA of the BAL fluid from bleomycin-treated rats on day 6 was significantly decreased by its treatment with various thrombin inhibitors, such as alpha 1-protease inhibitor, antithrombin III, hirudin, and MD-805. In our assay, purified rat thrombin also showed FGA in vitro, and its FGA was inhibited by the same concentrations of these thrombin inhibitors as those inhibiting the activity in the BAL fluid. On ammonium sulfate fractionation, most of the thrombin activity was recovered in the fraction of 35 to 50% saturation in which most of the FGA was detected. These results suggest that the FGA of the BAL fluid from bleomycin-treated rats was at least partly due to thrombin is responsible, at least in part, for fibroblast growth and pulmonary fibrosis in bleomycin-induced interstitial lung disease.

Ammonium Sulfate↗

Acute respiratory failure and pulmonary fibrosis secondary to administration of mycophenolate mofetil.

BACKGROUND: We report the first documented case of pulmonary toxicity to mycophenolate mofetil in this article. METHODS: A 51-year-old woman experienced systemic reactions beginning 10 days after cadaveric renal transplantation. RESULTS: Recurrent respiratory failure and documented progressive pulmonary fibrosis ensued. Cultures were negative and other agents were discontinued. It was not until the mycophenolate was stopped did the patient improve. CONCLUSIONS: Mycophenolate mofetil can cause acute respiratory failure simulating opportunistic infection or pulmonary edema. If not recognized, this may lead to the rapid development of severe pulmonary fibrosis, some of which may not be reversible.

Biopsy↗

Levels of cytokeratin 19 fragments in bronchoalveolar lavage fluid correlate to the intensity of neutrophil and eosinophil-alveolitis in patients with idiopathic pulmonary fibrosis.

Cytokeratin 19 (CK19) is a specific cytoskeletal structure for simple epithelia, including bronchial and alveolar epithelial cells (BAEC). Since CK19 is abundant in alveolar epithelial cells, and could be released from injured alveolar epithelium in idiopathic pulmonary fibrosis (IPF), we investigated the levels of CK19 fragments in the bronchoalveolar lavage fluids (BALF) of 16 patients with idiopathic pulmonary fibrosis (IPF) and 12 patients with sarcoidosis using enzyme-linked immunoassay. There were also 19 control subjects (10 asymptomatic smokers and nine non-smokers). BALF from the non-smokers as well as the asymptomatic smokers contained few CK19 fragments (0.2+/-0.2, 1.3+/-0.5 pg ml(-1) respectively). There were significantly high levels of CK19 in the BALF from patients with IPF (7.3+/-1.4 pg/ml; P<0.01 vs. control non-smoker). Even if the levels of CK19 were expressed as relative to the albumin concentration, significantly increased levels of CK19 fragments were noted in BALF from patients with IPF. However, these levels were not found in BALF from patients with sarcoidosis. Importantly, levels of CK19 fragment in BALF were significantly correlated to the number of neutrophils (r = 0.791, P<0.001) and eosinophils (r = 0.771, P<0.001) but not to that of macrophages or lymphocytes in BALF from IPF patients. Our results suggest the usefulness of CK19 measurement in BALF for assessing the presence of bronchiolo-alveolar epithelial injuries in idiopathic pulmonary fibrosis.

Aged↗

Rat lung fibroblast collagen metabolism in bleomycin-induced pulmonary fibrosis.

Endotracheal bleomycin administration in rats and other animal species causes rapid development of pulmonary fibrosis, characterized by increased lung collagen synthesis and deposition. To clarify the mechanism, lung fibroblasts from bleomycin-treated rats (BRF) were isolated and maintained in tissue culture. They were then compared with those from normal untreated control animals, with respect to several key parameters of collagen metabolism. BRF synthesized collagen at a rate 35-82% above normal rat lung fibroblasts (NRF). This difference did not appear to be due to the selection of a clone by the subculture process. Furthermore, analysis of newly synthesized collagen type composition, revealed a significantly lower ratio of type III to type I collagen. Noncollagenous protein synthesis, however, was not significantly different from normal. Collagenase production and growth rate were also unaffected. BRF, however, was morphologically indistinguishable from NRF, even at the ultrastructural level. Upon further bleomycin (1 microgram/ml) exposure in vitro, BRF could be further stimulated to synthesize collagen at 82% above the rate for untreated BRF. This is comparable to the 90% increase in NRF treated in vitro (compared with untreated NRF). These results would favor the conclusion that bleomycin induces pulmonary fibrosis, by causing directly and/or indirectly lung fibroblasts (or a certain line of lung fibroblasts) to synthesize collagen at a higher rate without any associated increase in growth rate. The data, however, do not rule out the possibility that the fibroblast isolation procedure has selected for a certain population of fibroblasts that may not be typical of the in vivo situation.

Animals↗

Increased D allele frequency of the angiotensin-converting enzyme gene in pulmonary fibrosis.

An insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme has previously been studied extensively in relationship to cardiovascular and renal disease. The deletion/deletion (D/D) genotype is associated with a poor outcome in immunoglobulin (Ig) A nephropathy. However, the association of this genetic marker in cardiovascular and renal disease has generated controversy, with the exception of the rate of progression and therapeutic responsiveness in IgA nephropathy. Many of the same cytokines and polypeptide mediators involved in fibrosis of the cardiovascular and renal systems have been shown to be involved in pulmonary fibrosis. We examined the I/D polymorphism of the angiotensin-converting enzyme in a group of 24 patents with interstitial pneumonia and moderate to severe pulmonary fibrosis defined by radiographic studies, pulmonary function tests, and histologic findings. The incidence of the D allele in this study population was 69.0%, which is approximately 15.0% higher than the incidence in the general population of 54.0%. The incidence of the D/D genotype was 42.0%, which is approximately 11.0% greater than that in the general population (31.0%). The distribution of the D/D, I/D, and insertion/insertion genotypes of these 24 patients was not significantly different from that of historical controls (P =.1; chi(2) test); there were marginally significantly more D alleles among the 48 observed alleles than would be expected (P =.04).

Adult↗

Changes of lung surfactant and pressure-volume curve in bleomycin-induced pulmonary fibrosis.

We investigated whether alveolar surface force increased and participated in the lung pressure-volume relationship in bleomycin-induced pulmonary fibrosis in hamsters and, if so, whether lung surfactant was hampered in the lungs. On the air-filled pressure-volume curve, decreases of lung volume from control level were significantly higher at 3-8 cmH2O pressure on day 10 than on day 30. Because the change of lung tissue elasticity evaluated from the saline-filled pressure-volume curve was equal for the 2 days, the higher decrease of air volume on day 10 was due primarily to contribution of alveolar surface force. Pressure differences between deflation limbs of air-filled and saline-filled pressure-volume curves, which represented net alveolar surface force, were significantly higher at any lung volume between 50 and 90% total lung capacity on day 10, but almost no significance was observed on day 30. Phospholipid concentration in bronchoalveolar lavage fluid significantly decreased on day 10 but had improved by day 30. Analysis of phospholipid species in purified lung surfactant showed decreased fractions of disaturated phosphatidylcholine and phosphatidylglycerol on day 10. Surface-active properties of the surfactant, measured by a modified Wilhelmy balance, were remarkably hampered on day 10, but most of them had improved by day 30. We consider that the quantitative and functional abnormalities of lung surfactant have a part in the aggravation of lung mechanics in the acute phase of pulmonary fibrosis.

Animals↗

Elevated serum KL-6 levels in patients with systemic sclerosis: association with the severity of pulmonary fibrosis.

BACKGROUND: Serum KL-6 has been suggested to be a useful marker for the evaluation of interstitial lung disease activity. OBJECTIVE: To determine the correlation between serum KL-6 levels and pulmonary fibrosis in patients with systemic sclerosis (SSc). METHODS: Serum samples from patients with limited cutaneous SSc (lSSc; n = 19), diffuse cutaneous SSc (dSSc; n = 26) and normal individuals (n = 15) were examined by ELISA. RESULTS: Serum KL-6 levels in SSc patients were significantly higher than those in normal controls. KL-6 levels in dSSc patients were significantly elevated compared with those in lSSc patients. Elevated KL-6 levels were associated with the presence of pulmonary fibrosis in SSc patients or dSSc patients. Furthermore, KL-6 levels inversely correlated with percentages of diffusion capacity of carbon monoxide and vital capacity in SSc patients or dSSc patients. CONCLUSION: KL-6 may be a simple, serologic indicator for the severity of pulmonary fibrosis in SSc.

Adult↗

Bleomycin-induced pulmonary fibrosis in transgenic mice that either lack or overexpress the murine plasminogen activator inhibitor-1 gene.

Impaired fibrinolytic activity within the lung is a common manifestation of acute and chronic inflammatory lung diseases. Because the fibrinolytic system is active during repair processes that restore injured tissues to normal, reduced fibrinolytic activity may contribute to the subsequent development of pulmonary fibrosis. To examine the relationship between the fibrinolytic system and pulmonary fibrosis, lung inflammation was induced by bleomycin in transgenic mice that either overexpressed or were completely deficient in murine plasminogen activator inhibitor-1 (PAI-1). 2 wk after 0.075 U of bleomycin, the lungs of transgenic mice overexpressing PAI-1 contained significantly more hydroxyproline (118 +/- 8 micrograms) than littermate controls (70.5 +/- 8 micrograms, P < 0.005). 3 wk after administration of a higher dose of bleomycin (0.15 U), the lung hydroxyproline content of mice completely deficient in PAI-1 (49 +/- 8 micrograms) was not significantly different (P = 0.63) than that of control animals receiving saline (37 +/- 1 micrograms), while hydroxyproline content was significantly increased in heterozygote (77 +/- 12 micrograms, P = 0.06) and wild-type (124 +/- 19 micrograms, P < 0.001) littermates. These data demonstrate a direct correlation between the genetically determined level of PAI-1 expression and the extent of collagen accumulation that follows inflammatory lung injury. These results strongly support the hypothesis that alterations in fibrinolytic activity influence the extent of pulmonary fibrosis that occurs after inflammatory injury.

Animals↗

Smad3 null mice develop airspace enlargement and are resistant to TGF-beta-mediated pulmonary fibrosis.

Transforming growth factor-beta 1 plays a key role in the pathogenesis of pulmonary fibrosis, mediating extracellular matrix (ECM) gene expression through a series of intracellular signaling molecules, including Smad2 and Smad3. We show that Smad3 null mice (knockout (KO)) develop progressive age-related increases in the size of alveolar spaces, associated with high spontaneous presence of matrix metalloproteinases (MMP-9 and MMP-12) in the lung. Moreover, transient overexpression of active TGF-beta 1 in lungs, using adenoviral vector-mediated gene transfer, resulted in progressive pulmonary fibrosis in wild-type mice, whereas no fibrosis was seen in the lungs of Smad3 KO mice up to 28 days. Significantly higher levels of matrix components (procollagen 3A1, connective tissue growth factor) and antiproteinases (plasminogen activator inhibitor-1, tissue inhibitor of metalloproteinase-1) were detected in wild-type lungs 4 days after TGF-beta 1 administration, while no such changes were seen in KO lungs. These data suggest a pivotal role of the Smad3 pathway in ECM metabolism. Basal activity of the pathway is required to maintain alveolar integrity and ECM homeostasis, but excessive signaling through the pathway results in fibrosis characterized by inhibited degradation and enhanced ECM deposition. The Smad3 pathway is involved in pathogenic mechanisms mediating tissue destruction (lack of repair) and fibrogenesis (excessive repair).

Animals↗

[Lung transplantation for pulmonary fibrosis: perioperative morbidity and mortality].

Lung transplantation has become a valid therapeutic option for patients with pulmonary fibrosis in terminal stage, and the number of such interventions has increased exponentially in recent years. We undertook a retrospective study of 46 pulmonary fibrosis patients who received lung transplants from 1992 through 2002 with the aim of describing the most common intra- and early postoperative complications in the recovery unit. We also aimed to analyze the impact of each complication on mortality during the study period. The most frequent complications during surgery were reperfusion syndrome (47.5%), hemodynamic instability (41%), arrhythmias (23.9%), and pulmonary hypertension (15%), with exitus secondary to reperfusion syndrome. The most common postoperative complications were infection (56.5%), reimplantation response (45.7%), and kidney failure (19.6%). Overall mortality during the study period was 23.9%. The following complications were statistically significant in the univariate analysis of the relation with mortality: reperfusion syndrome (p=0.039), reimplantation response (p=0.039), kidney failure (p=0.013), rejection (p=0.016), and sepsis (p<0.001). The only complication that remained significant in the multivariate analysis was sepsis (p<0.001). In spite of the considerable progress made, intra- and postoperative complications continue to be a real threat for the transplanted lung patient. Sepsis was the strongest predictor of poor prognosis in the early recovery period.

Female↗

[Proliferation of pulmonary fibroblasts obtained from rats with bleomycin-induced pulmonary fibrosis and effects of rat rIL-1 alpha on this proliferation].

To clarify the mechanism of pulmonary fibrosis, the growth rate of fibroblasts obtained from bleomycin (BLM)-treated rats was compared with that of fibroblasts obtained from control rats. Proliferation of fibroblasts obtained from rats at 4 days after BLM instillation (BRF) was significantly more rapid than that of fibroblasts obtained from rats at 4 days after saline instillation (CRF), as assessed by cell counting and 3H-TdR incorporation. CRF and BRF were separated by the method of discontinuous Percoll gradients. Three fibroblast fractions of specific gravity (S.G.), S.G. < 1.036, 1.036 < or = S.G. < 1.050, 1.050 < or = S.G. < 1.062, were obtained. Percentages of the densest fibroblast fraction were 46.2 +/- 5.2 in BRF and 6.4 +/- 2.8 in CRF. The densest fibroblasts in BRF proliferated more rapidly than the least dense fibroblasts. Rat rIL-1 alpha suppressed the proliferation of CRF and BRF, dose dependently. These results suggest that an increase in the densest fibroblasts in the lung might correlate with BLM-induced pulmonary fibrosis and that IL-1 alpha suppresses the proliferation of pulmonary fibroblasts.

Animals↗

Altered accessory cell function of alveolar macrophages: a possible mechanism for induction of Th2 secretory profile in idiopathic pulmonary fibrosis.

Alveolar macrophages (AMs) are considered to play a central role in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Recent studies have revealed a predominance of the type-2 T-helper (Th2) cytokine pattern of inflammatory response in the pulmonary interstitium in IPF. The aim of the present study was to determine whether or not the altered accessory cell function of AMs could account for the Th2 pattern of chronic inflammation in IPF. The levels of various cytokines were measured in the supernatants of soluble anti-CD3 monoclonal antibody (MoAb)-stimulated T-cells, co-cultured with autologous AMs, by enzyme-linked immunosorbent assay (ELISA). Cells from six patients with IPF and from nine normal volunteers (five nonsmokers and four smokers) were examined. The inhibitory effect of interleukin (IL)-10 on the accessory cell function of AMs and the expression of CD80 and CD86 on AMs were also investigated. IL-4 and IL-5 levels were significantly higher in the co-cultures from patients with IPF than in those from normal volunteers. IL-2, interferon-gamma (IFN-gamma), and IL-10 production in these co-cultures did not differ. IL-10 suppressed T-cell proliferation in co-cultures with AMs from healthy volunteers (smokers and nonsmokers), but not with AMs from patients with IPF. Expression of CD80 and CD86 on AMs from these groups did not differ. Thus, the altered accessory cell function of alveolar macrophages from patients with idiopathic pulmonary fibrosis may possibly relate to the pattern of type-2 T-helper cytokine production in response to inflammation.

Adult↗

Effects of fish oil treatment on bleomycin-induced pulmonary fibrosis in mice.

Bleomycin is an antibiotic used to treat a variety of neoplasms. A major side-effect of bleomycin therapy is the induction of an intense inflammatory response that develops into pulmonary fibrosis. Several studies have shown that certain polyunsaturated fatty acids found in fish oil reduce the inflammatory response in vivo. Fish oil has been employed for the treatment of several pathologies such as glomerulonephritis, cardiovascular diseases, rheumatoid arthritis, and even as an adjuvant in cancer therapy. This study examined the effects of fish oil treatment on the development of bleomycin-induced pulmonary fibrosis. Mice were intraperitoneally treated with bleomycin or with saline daily for 10 days, and 15 days after the last injection they started to receive fish oil by gavage for 14 days. The lungs were processed for light microscopy, biochemical and immunohistochemical investigations. Fish oil did not prevent the development of pulmonary fibrosis after the injury as shown by light microscopy, cytokines immunohistochemical analysis, TBARS content and protein levels in the lung. In addition however, fish oil itself induced a slight inflammatory process in the lung, as observed by the increase in cellularity, vasodilatation in the lung parenchyma, TBARS content, and a slight increase in the lung protein content.

Actins↗

Plasma and pulmonary pharmacokinetics of bleomycin in murine strains that are sensitive and resistant to bleomycin-induced pulmonary fibrosis.

Previous studies have shown that C57Bl/6N mice are sensitive and BALB/c mice are resistant to the pulmonary fibrotic effects of bleomycin (BLM). We assessed the plasma elimination and pulmonary content of BLM in C57Bl/6N and BALB/c mice treated with a single dose of [3H]BLM (80 mg/kg i.v.) to determine whether these murine strains show corresponding differences in BLM pharmacokinetics and pulmonary disposition after systemic administration of the drug. Serial blood samples were obtained from each animal and lungs were collected after pulmonary lavage or vascular perfusion with saline. Administration of BLM (80 mg/kg i.v.) produced significant elevations in lung hydroxyproline (35%) in C57Bl/6N but not in BALB/c mice. In contrast, BALB/c mice were more sensitive to pulmonary fibrosis induced with cyclophosphamide (200 mg/kg i.p.) compared to C57Bl/6N mice, indicating that strain sensitivity to pulmonary fibrosis is drug specific in these mice. BLM showed first order plasma elimination kinetics over 30 min in both strains with a shorter half-life in the sensitive strain (9.6 +/- 0.3 min in C57Bl/6N vs. 12.7 +/- 1.9 min in BALB/c). Plasma elimination deviated from first order kinetics after 30 min in both strains and plasma levels of BLM were up to 2-fold higher in the resistant strain over a 3-hr time course. Radioactivity in saline-perfused lungs was also significantly higher (1.5-2-fold) in BALB/c mice for least 1 hr after BLM injection. A similar fraction of the total lung radioactivity (approximately 80%) was recovered from both strains by pulmonary lavage, suggesting that BLM enters the alveolar spaces relatively freely in each strain.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗